I hear you, and I'm still at the beginning.
I have a 1-and-a-half year old. I'm very lucky because I work from home, my wife doesn't work and I'm in a good work-life balance situation (good company).
The incredible advantage of working at home and being a Software Developer is that I don't need to sit at a computer all the time to do my job. Good chunk of it is thinking through a problem, I can do that while I lay on the floor and let my baby crawl on me ;)
That being said, I can relate. I end up an entire week where all I did was work, get groceries, get other stuff from somewhere else.
I did try to optimize my time though: when I'm in the washroom, sitting on the throne, I read 5-10 pages of a book instead of my RSS feed (I leave that to the moments when I'm too tired). That over the course of 1 years adds up, I almost finished 4 books, which is a lot with a kid!
I got a tablet to stream my PC there, so that I can play a few videogames when in bed, however most of the time I just fall asleep or play 30 minutes at most. I need 10 hour to get decent rest (the baby moves/do stuff during the night. Yes she sleeps with us, otherwise we would get 1 hour of sleep).
Audiobooks have proven very helpful, I listen to those when going to buy groceries, I manage to keep growing while I wait to get back my time.
What I'm missing the most is time with my wife. I mean, we stay all day together, but we rarely get to play something together. We recently made a big purchase: a board game table. This should allow us to play when the baby naps and keep the board game set, so hopefully we can go back to play board games without having to wait 4-5 years.
That's all the "wisdom" I have to offer. I bet you already figured out all of it since you are further in the parenting voyage, but in case you missed it, that's my 2-cents, hope it's of some help.
That being said, I do love my baby. Some weeks I really need that 1 hour of gaming or reading, otherwise I go crazy, but most of the time is either work or kids.
Some weeks I just need 10 minutes hugging with my wife, to recover lack of "us" time